A corpora



Patented Jan. 6, .931

, UNITED STATES- PATENT; OFFIC WHEELER G. LOVELL 'AND THOMAS A. BOYD, OFDETROIT, MICHIGAN, ASSIGNORS TO GENERAL MOTORS RESEARCH TION OF DELAWAREI CORPORATION, OF DETROIT, MICHIGAN, A CORPORA- METHOD AND MEANS FOREEMOVING CARBON DEPOSITS No Drawing.

This application relates'to the removing of carbon deposits frominternal combustion engines, and its principal objects are to providechemical compounds which will readily loosen the deposits and a methodwhich will These aliphatic amines include the primary amines of whichisoamylamine, ethanolamine, benzylamine, ethylene, diamine monohydrate,and hydroxyethylamineare examples; the secondary amines of whlchdi-isomylamine and diethanolamine are examples, and the tertiary aminesof which tri-lsoamyl amine and triethanol amine are examples. We usethose aliphatic amines Wl11Cl1 boil above 150 F. to keep the carbonremover 1n the liquid state in a hot engine because the heat acceleratesthe solvent action of the liquid. Optimum conditions in a water cooledengine are to heat the parts to ]11St below the boiling point of waterand employ an a11- phatic amine which remains liquid at thattemperature.

By way of a specific example, we may run an engine until it is hot, thenintroduce into each cylinder about a tablespoonful of hydroxyethyl amineand let the engine set, preferably for an hour or more. After the engineis started the loosened carbon is blown out the exhaust. The. metalsurfaces can also be cleaned by wiping the deposit oil".

The carbon remover dissolves in the binder of the carbon coating, or thetwo may be mutually soluble, causing the binder and the deposit as awhole to swell. The heat developed when the engine is started drives thesolvent and some of the binder away leaving asomewhat porous anddisintegrated mass which is lightly held together and the rush ofApplication filed August 24, 1928, Serial No. 301,942.

Other compounds, such as aniline, furfurerr etc., which have a solventaction on varnish, may be employed with the aliphatic amines.

We clai. I. The process of cleaning carbon deposits from an ljnternalcombustion engine which comprisesheating the carbon coated parts,

placing on; the carbon deposit an aliphatic amine which boils above 150F., and removing the deposit. a

2. The process of cleaning a carbon deposit from an internal combustionengine which comprises running the engine until the carbon coated partsare heated, dissolving into the binder of the deposit an aliphatic aminewhich boils above 150 F., and blowing the loosened carbon out of theengine exhaust.

3. The process of cleaning a carbon deposit from an internal combustionengine which comprises running the engine until the carbon coated partsare heated, dissolving into the binder of the deposit a primary aliphatic amine which boils above 150 F., and blowing the loosened carbonout the engine exhaust?" a 4. The process of cleaning a carbon depositfrom an internal combustion engine which comprises running the engineuntil the carbon coated parts are heated, dissolving into the binder ofthe deposit hydroxyethylamine, and blowing the loosened carbon out theengine exhaust. I

5. The process of cleaning carbon deposits from alrinternal combustionengine which comprises heating the carbon coated parts, placing on thecarbon deposit a primary aliphatic amine which boils above 150 F., andremoving the deposit.

6. The process of cleaning carbon deposits from an internalcombustionengine which comprises heating the carbon coated parts,placing on the carbon deposit hydroxyethyl amine, and removing thedeposit.

5 7. A carbon removing compound com rising-an aliphatic amine whichboils a ove 150 F., and a solvent for varnish.

8. A carbon removing compound comprising a primary aliphatlc amine whichboils 0 above 150 F., and a solvent for varnish.

' 9. A carbon removing compound comprising hydroxyethylamine, and asolvent for varnish.

10. A carbon removing compound comprising an aliphatic amine which boilsabove 150 F., and alcohol.

11. A carbon removing compound comprising a primary ali hatic aminewhich boils above 150 R, an alcohol.

12. A carbon removing compound comprising a primary aliphatic aminewhich boils above 150 F., benzol and alcohol.

13. A carbon removing compound comr prising an aliphatic amine whichboils above 150 F. alcohol and benzol.

In testimony whereof we afiix our signatures.

WHEELER G. LOVELL.

\ MAS A. BOYD.

